The group move towards a goal.
a.
social roles
b.
individual roles
c.
leadership roles
d.
task roles

Individual roles! It is the groups individual effort to complete the task at hand. Not necessarily a leader because the leader wouldn't be able to complete the task at hand alone, therefore it is the groups individual effort.

The answer is d) task roles

Task roles are key for understanding the use they turn to be in order to accomplish goals set as a group. There are many task roles, and someone can act in several roles, for example, a leader o a group of persons can engage in a project and determine how to move onwards.

Task roles do not limit to a single person yet is usually the task Leader is a person that helps a group to focus on the primary objectives by setting a specific agenda, controls the participants and communication between the group’s members, evaluates new ideas as well as contributions of participants involved.

Some other task roles: Information Gatherers, helped by Opinion Gatherers, The Devil’s Advocate, together all they account for orienting the group towards a goal as a unity.

those sounds of the natural world are bioacoustics, and they're more than a false-color spectrogram of data from the musiamunat conservation area.

answer; eliminate parking problems in cities, because a car took up only half as much space as a horse and buggy;